Ladders commercially available today seldom have leveling or extension legs as a part thereof. Devices to extend the legs of ladders are well known and range from primitive approaches of placing blocks or rocks under the ladder leg to permanently attached extension members such as illustrated in U.S. Pat. No. 2,318,017.
Generally when a member such as a ladder leg is extended, the ladder leg is inherently weakened due to its increased lever arm or due to the technique of attachment and its concentration of forces in a localized region which cause a bending movement on the leg.
Further with the extension members of the prior art, the ladder still does not have additional tendency to overcome twisting which is a major form of instability. The two support points are also displaced from a line parallel to the wall or other structure against which the ladder is leaning. This displacement poses a potential hazard particularly on surfaces sloping down and away from the structure supporting the upper end of the ladder. On such surfaces, the forces are such that a twisting and sliding force is generated.
Additional hazards are present when a single foot or support point extension is used since in many instances the down slope footing or support is not as stable as the up slope footing and this may create a tipping force mismatch.